U.S. patent application number 13/978353 was filed with the patent office on 2014-01-16 for winding shaft drive for operating a retractable architectural covering and shaft brake module for use therein.
This patent application is currently assigned to Hunter Douglas Industries BV. The applicant listed for this patent is Jorg Bohlen. Invention is credited to Jorg Bohlen.
Application Number | 20140014280 13/978353 |
Document ID | / |
Family ID | 45446055 |
Filed Date | 2014-01-16 |
United States Patent
Application |
20140014280 |
Kind Code |
A1 |
Bohlen; Jorg |
January 16, 2014 |
WINDING SHAFT DRIVE FOR OPERATING A RETRACTABLE ARCHITECTURAL
COVERING AND SHAFT BRAKE MODULE FOR USE THEREIN
Abstract
A winding shaft drive (1, 1A, 101, 101A, 102, 102A) is arranged
for operating a retractable covering for an architectural opening.
The winding shaft drive includes an at least partially hollow
winding shaft (7); a driving member (3, 103) for inducing rotation
to the winding shaft; and a shaft brake adapted to be operated by
the driving member. The shaft brake includes a preassembled module
(5) for accommodation in the at least partially hollow winding
shaft (7) and has first coupling means (67) on one axial end
thereof for transmitting rotative forces and second coupling means
(69) on the same one axial end for transmitting non-rotative
stationary forces. The driving member has a driving hub (11, 111)
for removably coupling to the first coupling means (67) and a
stationary connector (17, 17A, 117, 117A) for removably coupling to
the second coupling means (69). A shaft brake module (5) and a
driving member (3, 103) are specifically adapted for use in the
winding shaft drive.
Inventors: |
Bohlen; Jorg; (Langen,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bohlen; Jorg |
Langen |
|
DE |
|
|
Assignee: |
Hunter Douglas Industries
BV
Rotterdam
NL
|
Family ID: |
45446055 |
Appl. No.: |
13/978353 |
Filed: |
January 5, 2012 |
PCT Filed: |
January 5, 2012 |
PCT NO: |
PCT/EP12/00037 |
371 Date: |
October 1, 2013 |
Current U.S.
Class: |
160/291 |
Current CPC
Class: |
E06B 9/78 20130101; E06B
2009/785 20130101; E06B 9/42 20130101 |
Class at
Publication: |
160/291 |
International
Class: |
E06B 9/42 20060101
E06B009/42; E06B 9/78 20060101 E06B009/78 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 6, 2011 |
EP |
11000065.0 |
Claims
1. Winding shaft drive for operating a retractable covering for an
architectural opening, including: an at least partially hollow
winding shaft; a driving member for inducing rotation to the
winding shaft; and a shaft brake adapted to be operated by the
driving member, wherein the shaft brake includes a preassembled
module for accommodation in the at least partially hollow winding
shaft and having first coupling means on one axial end thereof for
transmitting rotative forces and second coupling means on the same
one axial end for transmitting non-rotative stationary forces, and
wherein the driving member has a driving hub for removably coupling
to the first coupling means and a stationary connector for
removably coupling to the second coupling means.
2. Winding shaft drive according to claim 1, wherein the shaft
brake module has a stationary shaft associated with the second
coupling means, and wherein an end of the stationary centre shaft
is exposed at an end of the shaft brake module opposite of the
second coupling means and adapted to be coupled to a connector
sleeve of a spring assist module.
3. Winding shaft drive according to claim 1 or 2, further
comprising a spring assist module.
4. Winding shaft drive according to claim 1 or 2, wherein the shaft
brake module includes any one of a selected number of wrap springs
acting as a braking element.
5. Winding shaft drive according to claim 4, wherein the shaft
brake module includes an inner brake sleeve for frictional
engagement by the or each wrap spring, and wherein the inner brake
sleeve has a lubrication groove helically wound about an outer
friction surface thereof.
6. Winding shaft drive according to claim 1, wherein the shaft
brake module and the driving member can be coupled to one another
in a plurality of relative rotational positions by predefined
increments.
7. Winding shaft drive according to claim 6, wherein the first
coupling means include internal splines on the shaft brake module
for coupling with corresponding splines on the driving hub.
8. Winding shaft drive according to claim 6 or 7, wherein the
second coupling means include a splined end section on a stationary
centre shaft for coupling with corresponding splines on the
stationary connector.
9. Winding shaft drive according to claim 1, wherein the first
coupling means has an undercut area at an axial end adapted to face
the driving hub, to allow the winding shaft to engage the driving
member at an angle with respect to an aligned position in which it
is finally mounted.
10. Winding shaft drive according to claim 1, wherein the
stationary connector has a widened area for receiving the second
coupling means at an angle with respect to an aligned position in
which it is finally mounted.
11. Winding shaft drive according to claim 1, wherein the driving
member also has an integral shaft brake.
12. Winding shaft drive according to claim 11, wherein the integral
shaft brake includes a wrap spring holder ring.
13. Winding shaft drive according to claim 12, wherein the wrap
spring holder ring has inwardly directed rims on each of its axial
end faces.
14. Winding shaft drive according to claim 1, wherein the driving
member includes a bail bearing interposed between a housing and the
driving hub.
15. Winding shaft drive according to claim 1, wherein the driving
member includes a chain wheel and an operating chain.
16. Winding shaft drive according to claim 15, wherein the
operating chain includes a chain stopper for defining an end of
travel for the driving chain and adapted to define one of a fully
retracted or fully extended positions of the winding shaft.
17. Winding shaft drive according to claim 15 or 16, wherein the
operating chain is guided over a chain guide surface, wherein the
chain guide surface is of a relatively hard and wear resistant
material, and wherein the chain guide surface is relatively thin
and supported on a relatively soft and resiliently flexible
material for noise reduction.
18. (canceled)
19. (canceled)
Description
[0001] The invention relates to a winding shaft drive for operation
of a retractable covering for an architectural opening. Winding
shaft drives for window coverings, where lift cords, or a flexible
screening member are wound onto the winding shaft, such as in
roller blinds, are generally known.
[0002] The known winding shaft drives for window coverings usually
require a shaft brake to prevent the retracted screening member
from returning to its extended position under its own weight. Such
shaft brakes are conveniently integral with a drive member for
rotating the winding shaft. Because window coverings come in
various sizes, to cover relatively small architectural openings, as
well as relatively large architectural openings. The required shaft
brake force increases with the size of the window covering and it
has often been necessary to provide drive members with differently
sized shaft brakes, to enable the offering of an adequate range of
window coverings. For reasons of stock keeping and ease of
manufacture there is a continuing demand for reducing the number of
different components. Moreover accommodating the larger sizes of
shaft brakes into the driving member has also encountered limits in
shape and size. Further it has also become popular to use spring
assistance in retractable window coverings to counter the extra
weight of larger sizes, so that manual or motor driven operation is
less affected by gravity. One problem with such spring assistance
is that pretensioning or preloading of the spring assistance is
critical and difficult to adjust by the installer. One example of
the prior art is described in U.S. Pat. No. 7,497,242.
[0003] Accordingly it is an object of the present invention to
propose an improved driving mechanism for a winding shaft of an
architectural covering. In a more general sense it is thus an
object of the invention to overcome or ameliorate at least one of
the disadvantages of the prior art. It is also an object of the
present invention to provide alternative structures which are less
cumbersome in assembly and operation and which moreover can be made
relatively inexpensively. Alternatively it is also an object of the
invention to at least provide the public with a useful choice.
[0004] To this end the invention provides a driving mechanism for
operating a winding shaft of a retractable architectural covering,
or a retractable covering for an architectural opening, the winding
shaft drive including: an at least partially hollow winding shaft;
a driving member for inducing rotation to the winding shaft; and a
shaft brake adapted to be operated by the driving member, wherein
the shaft brake includes a preassembled module for accommodation in
the at least partially hollow winding shaft and having first
coupling means on one axial end thereof for transmitting rotative
forces and second coupling means on the same one axial end for
transmitting non-rotative stationary forces, and wherein the
driving member has a driving hub for removably coupling to the
first coupling means and a stationary connector for removably
coupling to the second coupling means. When the weight of a window
covering, to be operated by the winding shaft drive of the
invention, exceeds the capacity of the holding force of the driving
member, the shaft brake module can provide additional braking
torque. By separating the shaft brake function from the driving
member, with which it is conventionally associated, it also is
possible to reduce the volume necessary for the driving member and
thereby minimalise any light gaps at the sides of a window
covering, such as roller shades.
[0005] In connection with the invention it is particularly
advantageous when the shaft brake module has a stationary shaft
associated with the second coupling means, and wherein an end of
the stationary centre shaft is exposed at an end of the shaft brake
module opposite of the second coupling means and adapted to be
coupled to a connector sleeve of a spring assist module. This can
moreover be very useful when the winding shaft drive is further
comprising a spring assist module. In this combination the shaft
brake module can be coupled with the spring assist module. When the
spring assist module and the shaft brake module are preassembled
into the at least partly hollow winding shaft, then the spring
assist module can be pretensioned or preloaded. The pretension or
preload of the spring assist module will then be conveniently
maintained by the shaft brake module. The end user or window
covering installer thereby do not have to worry about any
adjustment op the spring assist module prior to use, as these
adjustments can be factory set.
[0006] It is further preferred that the shaft brake module includes
any one of a selected number of wrap springs acting as a braking
element. In the embodiment that will be described up to four wrap
springs can be mounted on an inner brake sleeve. In this regard it
is further preferred that the inner brake sleeve, for frictional
engagement by the or each wrap spring, has a lubrication groove
helically wound about an outer friction surface thereof. To prevent
noise and wear, lubrication grease is conventionally used in wrap
spring brakes. As a result of the substantially flat contact
surfaces created by square section spring wire cross section and
smooth outer surfaces of the inner brake sleeve, the distribution
of the lubrication grease has at times been somewhat erratic,
resulting in creaking noises already after a few operating cycles.
The provision of this helical lubrication groove has significantly
improved the distribution of lubrication grease, with no noticeable
effect on the effectiveness of the friction surface itself.
[0007] In a further preferred arrangemenmt the shaft brake module
and the driving member can be coupled to one another in a plurality
of relative rotational positions by predefined increments. This can
advantageously be achieved when the first coupling means include
internal splines on the shaft brake module for coupling with
corresponding splines on the driving hub. Similarly the second
coupling means can include a splined end section on a stationary
centre shaft for coupling with corresponding splines on the
stationary connector. To connect the shaft brake module and the
driving member, these parts may thereby be mated together in a
plurality of different relative positions. This may in particularly
be helpful when the driving member has defined end positions, as is
often the case.
[0008] Further it is advantageous, when the first coupling means
has an undercut area at an axial end adapted to face the driving
hub, to allow the winding shaft to engage the driving member at an
angle with respect to an aligned position in which it is finally
mounted. In this regard it is also preferred when the stationary
connector has a widened area for receiving the second coupling
means at an angle with respect to an aligned position in which it
is finally mounted. When installing or removing the winding shaft
to or from an already installed driving member the undercut area
and the widened area, allows the winding shaft to be presented at
an angular position, so that each of its ends may be connected one
after the other, rather than at the same time. This avoids putting
force on the coupling elements and protect these from becoming
damaged.
[0009] In one embodiment of the invention the driving member can
also have itself an integral shaft brake. This arrangement is
useful when the shaft brake integrated in the driving member is not
sufficient for holding a particular winding shaft in position. The
shaft brake module is then employed as an additional auxiliary
shaft brake, to increase the holding force of the drive member.
This may be necessary when the window covering to be retracted by
the winding shaft exceeds the maximum dimensions for which the the
driving member with its integral shaft brake is designed. Also when
spring assistance is desired for a particular window covering, that
is to be operated by the winding shaft drive, it may be useful to
employ a separate auxiliary shaft brake module in accordance with
the invention. In a driving member with an integral shaft brake, an
advantageous arrangement may includes a wrap spring holder ring.
Use of a wrap spring holder ring greatly enhances the ease of wrap
spring handling and assembly thereof in the driving member. Such a
wrap spring holder ring may also advantageously have inwardly
directed rims on each of its axial end faces. These inwardly
directed rims exactly position the wrap spring on its braking
surface and ensures that brake forces will be identical in both
directions of rotation.
[0010] To minimise friction the driving member may include a ball
bearing that is interposed between a housing thereof and the
driving hub. It is also preferred when the driving member includes
a chain wheel and an operating chain. The operating chain may
optionally also include a chain stopper for defining an end of
travel for the driving chain and adapted to define one of a fully
retracted or fully extended positions of the winding shaft. This
may make it necessary to first adjust the driving member as to the
opostion of the chain stopper, before mounting of the winding shaft
by means of the shaft brake module accommodated therein. When using
an operating chain, the operating chain may be guided over a chain
guide surface, wherein the chain guide surface is of a relatively
hard and wear resistant material, and wherein the chain guide
surface is relatively thin and supported on a relatively soft and
resiliently flexible material for noise reduction. For wear
resistance the guiding surface that will be touched by the
operating chain is preferably made of a relatively hard abrasion
resistant plastic. This however results in an increased noise
level. Supporting the hard guiding material on a relatively soft,
rubber-like plastic composition, has made it possible to silence
the chain operation.
[0011] The invention also provides a shaft brake module that has
one or more of the features disclosed and discussed herein.
Similarly the invention also provides a driving member with one or
more of the features disclosed herein.
[0012] Further advantages and preferences will be come clear from a
detailed description of some exemplary embodiments, in which:
[0013] FIG. 1 shows a first embodiment of winding shaft drive
according to the invention in an exploded arrangement;
[0014] FIG. 2 is an exploded arrangement of a variation of the
first embodiment having an additional spring assist module;
[0015] FIG. 3 shows the variation of FIG. 2 in its assembled
arrangement;
[0016] FIG. 4 is an enlarged view showing only the driving member
of the first embodiment;
[0017] FIG. 5 is an exploded view of the driving member of FIG.
4;
[0018] FIG. 6 is an exploded view of the auxiliary shaft brake
module shown in FIGS. 1 to 3;
[0019] FIGS. 7A and 7B are different perspective views of the brake
sleeve used in the auxiliary shaft brake module of FIG. 6;
[0020] FIG. 8 is a partly assembled auxiliary shaft brake module of
FIG. 6;
[0021] FIGS. 9A and 9B are different perspective views of the fully
assembled shaft brake module of FIG. 6;
[0022] FIGS. 10A and 10B are cross sections in the directions of
the arrows XA and XB in FIGS. 9A and 9B;
[0023] FIG. 11 is a second embodiment of winding shaft drive
according to the invention;
[0024] FIG. 12 is a winding shaft drive similar to FIG. 11, in
which the auxiliary shaft brake is replaced by a standard shaft
adapter;
[0025] FIG. 13 is an exploded view of the driving member shown in
FIGS. 11 and 12;
[0026] FIG. 14 is a partially exploded view of the operating chain
and low noise chain guide;
[0027] FIG. 15 is partially assembled representation of the
components of FIG. 14;
[0028] FIGS. 16A and 16B are full and partial cross sections of the
driving member showing angular connectivity of the auxiliary shaft
brake module;
[0029] FIG. 17 is an exploded view similar to FIG. 2 of the second
embodiment;
[0030] FIG. 18 is an assembled situation of the components shown in
FIG. 17; and
[0031] FIG. 19 is a longitudinal cross section of the second
embodiment, without auxiliary shaft brake module, but with a spring
assist module.
[0032] In FIG. 1 an exploded arrangement is shown of a winding
shaft drive 1 for operating a retractable covering for a
architectural opening. Such winding shaft drives may be employed to
wind lift cords of a retractable window covering, but also to wind
a flexible screening member, such as in roller blinds. Winding
shaft drives and their incorporation in various retractable window
coverings are generally well known to the skilled person, so that
the present description can be limited to the features of the
winding shaft drive in as far as these differ from the prior art.
The winding shaft drive 1, as shown in FIG. 1, includes a driving
member 3, a shaft brake module 5 and an at least partially hollow
winding shaft 7. The driving member 3 comprises a stationary
bracket part 9, a driving hub 11 that can be rotated by a chain
wheel, hidden from view in FIG. 1, by a swivelling chain cover 13
and is drivable by an operating chain 15. At the centre of the
driving hub 11 there is a stationary connector 17 that is
non-rotatably connected to the bracket part 9. As will be described
below, the shaft brake module 5 has a stationary centre shaft 19
that may be connected with the stationary connector 17 of the
driving member 3.
[0033] In FIG. 2 an exploded arrangement is shown of a variation
winding shaft drive 1, but for the optional addition of a spring
assist module 21. The spring assist module 21 is generally as
described in applicant's published international patent application
WO 2010/089118 and reference to this publication can be had for
further details of the spring assist module. In as far as the
present invention is concerned, it will only be mentioned that the
spring assist module 21 has a centre shaft 23 that has a
non-circular connector sleeve 25 on at least one longitudinal end
thereof for coupling to the stationary centre shaft 19 of the shaft
brake module 5. A helically wound torsion spring 27 surrounds the
centre shaft 23 and one end has a coupling flange 29 for coupling
to the hollow winding shaft, deleted from FIG. 2 for clarity, but
identical to the winding shaft 7 in FIG. 1. An opposite end of the
torsion spring 27 sits on a sleeve 31 by which it is coupled to the
centre shaft 23. As will be clear from the description given in
applicant's WO 2010/089118, the spring assist module 21 can be
dimensioned and/or pretensioned to compensate for the weight of
screening materials during extension and retraction of the winding
covering by the winding shaft drive.
[0034] FIG. 3 simply shows the components of FIG. 2 in their
assembled arrangement. It is also seen that the spring assist
module 21 has an idle bearing 33, which journals the stationary
centre shaft 23 in respect of the winding shaft. The winding shaft,
which is not shown in FIG. 3, accommodates the entire assembly of
spring assist module 21 and shaft brake module 5 within its hollow
interior. When the winding shaft is a roller blind roller, the fact
that it can extend up to the swivelling chain cover 13 results in a
very minimal light gap at the operating end of the roller blind,
where the operating chain 15 depends. This advantage has been
achieved by the shaft brake 5 being independent from the driving
member 3.
[0035] FIG. 4 shows the driving member 3 of the previous Figures on
a somewhat enlarged scale to make it easier to recognize the
various elements already described. FIG. 4 also serves to show that
the swivelling chain cover 13 not only allows deflection of the
loop of operating chain 15, but also to offer the option of having
the bracket part 9 in a position for overhead mounting.
[0036] FIG. 5 is an exploded view of the driving member 3 of FIG.
4. The driving hub 11 is part of a chain wheel 35. The chain wheel
35 rotates on a ball bearing 37 within the swivelling chain cover
that is comprised of a cover part 13A and a base part 13B. The
cover part 13A snap fits onto the base part 13B, so that the chain
wheel 35, ball bearing 37 and operating chain 15 are held together
on the bracket part 9 by the stationary connector 17A, being
non-rotatably received in the bracket protrusion 17B and secured by
connector pin 39.
[0037] FIG. 6 in an exploded arrangement shows the shaft brake
module 5. The shaft brake module 5 is comprised of a centre shaft
19 onto which an inner brake sleeve 41 is non-rotatably held by
means of a splined exterior section 43 on the centre shaft 19 and a
splined interior 45 of the inner brake sleeve 41. The brake sleeve
41 in this example can receive up to four individual wrap springs
47. The number of wrap springs 47 that will be used is a function
of the required braking force, which itself depends on the size of
the window covering that will be operated by the winding shaft
drive. An intermediate bearing disc 49 and an outer brake sleeve 51
accommodate the brake sleeve 41 and the wrap springs 47. Wrap
springs 47, which are frictionally engaging the brake sleeve 41,
each have radially extending tangs 53 on their opposite ends that
project through axially extending windows 55, 57 in the outer brake
sleeve 51. For reasons of symmetry and balancing of forces, the
outer brake sleeve 51 is provided with opposite windows 55, 57 and
the spring tangs 53 of the wrap springs 47 are positioned to
alternatingly being engaged by the axial edges of one window 55 or
the other window 57. The skilled person will know that it is also
possible to use only a single window on one side of the outer brake
sleeve 51 and with all the spring tangs 53 extending between the
axial edges of such a single window. Accommodating the components
of the shaft brake module is an outer housing 59. The outer housing
59 has inwardly extending key formations 61, 63, which confront the
respective windows 55, 57 of the outer brake sleeve 51. Reference
numeral 63 is pointing at the actual key formation, while reference
61 is merely pointing at its reverse side as it appears on the
exterior of the outer housing 59. Each of the key formations 61, 63
extends axially between opposite edges of the relevant windows 55,
57 and also between the spring tangs 53. For retaining the
described components of the shaft brake module 5 in an assemble
condition, a speed nut 65 is provided that engages the protruding
centre shaft 19. Further shown in FIG. 6 is that the outer brake
sleeve 51 has internal splines 67 on one end and that the centre
shaft 19 has a splined end section 69. For a preliminary
understanding of the working of the shaft brake module 5, it may be
helpful reverting to FIG. 1. When the shaft brake module 5 is
connected to the driving member 3, the internal splines 67 of the
outer brake sleeve will be engaged by the driving hub 11 for
rotation therewith. At the same time the splined end section 69 of
the centre shaft 19 will be engaging the stationary connector 17.
Rotation of the driving hub 11 by the operating chain will rotate
the outer brake sleeve 51, while the inner brake sleeve 41 is kept
stationary with respect to the bracket part 9. Rotation of the
outer brake sleeve 51 in either of its opposite rotational
directions will cause the relevant axially extending edge of the
window 55, 57 to engage the relevant spring tangs 53 in a direction
that opens the windings of the wrap springs 47. Thereby the wrap
springs are loosened from the inner brake sleeve and allowed to
rotate with the outer brake sleeve 51. Conversely when the windings
shaft 7 would induce rotational forces into the outer housing 59,
this would move the key formation 61, 63 to engage the relevant
spring tangs 53 in a direction that increases the grip of the wrap
springs 47 on the inner brake sleeve 41. Thereby any unwanted
movement of the window covering's screening material from an
adjusted position is effectively arrested. While the embodiment of
a shaft brake module described as an example uses one or more wrap
springs as a braking element, the skilled person will be aware of
alternative mechanisms that can be used instead. In particular it
would be possible to replace the wrap springs by a mechanism using
wedges or like clamping elements.
[0038] A further aspect of the inner brake sleeve 41 will now be
explained in reference to FIGS. 7A and 7B. The cylindrical outer
surface of the inner brake sleeve 41 is provided with a helical
groove 71 extending thereabout. This groove 71 provides the wrap
springs when seated on the inner brake sleeve 41 with lubrication
grease. To prevent noise and wear, lubrication grease is used in
wrap spring brakes, but as a result of the substantially flat
contact surfaces created by square section spring wire cross
section and smooth outer surfaces of the inner brake sleeve, the
distribution of the lubrication grease has been somewhat erratic.
The provision of the he heal lubrication groove 71 significantly
improves the distribution of lubrication grease, with no noticeable
effect on the friction surface.
[0039] FIG. 8 is an additional showing of the partly assembled
shaft brake module, before the outer housing is mounted. From FIG.
8 it is clear how the spring tangs 53 of the wrap springs 47 occupy
the axially extending windows in the outer spring sleeve 51.
Further, FIG. 8 helps to illustrate how the internal splines 67 and
the splined end section 69 of the centre shaft 19 are exposed on
one end for engagement with the driving hub 11 and stationary
connector 17 of the driving member 3.
[0040] FIGS. 9a and 9B show opposite isometric views of the
assembled shaft brake module 5. Indicated by arrows XA is the
direction of the cross section shown in FIG. 10A and indicated by
arrows XB the direction of the cross section shown in FIG. 10B. The
reference numerals used in FIGS. 8 through 10B have already been
described in reference to FIG. 6, so that repetition of such a
description in relation to FIGS. 8 through 10B is deemed
redundant.
[0041] In FIGS. 11 to 18 a further embodiment of winding shaft
drive according to the invention will be described. Additionally,
FIG. 19 shows one further variation of that embodiment. Reference
numerals used in these Figures will be identical to those used in
FIGS. 1 to 10B for identical components. Similar components will be
labelled by reference numerals differing a full "100" from those
used in FIGS. 1 to 10B.
[0042] Referring first to FIG. 11, there is shown an alternative
winding shaft drive 101 that differs from the winding shaft drive 1
of FIG. 1 by having a different driving member 103. The driving
member 103 includes a driving hub 111, a chain cover 113 and a
stationary connector 117. As will be explained below, the driving
member 103 has a shaft brake mechanism incorporated therein. As
shown in FIG. 12, the driving member 103 can therefore also
optionally be directly coupled to the winding shaft 7, by means of
standard shaft adapter 106, to form a winding shaft drive 102. The
standard shaft adapter 106 is here provided with a central opening
108 that communicates with the stationary connector 117 of the
driving member 103 for a purpose described below. In the winding
shaft drive assembly 101 according to FIG. 11, the shaft brake
module 5 is employed as an additional auxiliary shaft brake, to
enable the holding force of the drive member 103 to be increased.
This may be necessary when the window covering to be retracted by
the winding shaft exceeds the maximum dimensions for which the
shaft brake included in the driving member 103 is designed.
[0043] Reference to FIG. 13 will explain the differences of the
driving member 103 and its integral shaft brake. As shown in FIG.
13, the driving member 103 is assembled using the chain cover 113
as a basis. The chain cover 113 is provided with a protrusion 117B
that receives connector 117A in a non-rotatable manner. The chain
cover 113 is further provided with a shaft brake cavity 140 for
receiving wrap spring holder ring 142. The outer periphery of the
holder ring 142 and the inner periphery of the shaft brake cavity
140 have mating cavities and projections, so that the holder ring
142 is non-rotatably received in the cavity 140. The holder ring
142 has inwardly directed rims 144 on each of its axial ends to
hold an outwardly expanding wrap spring 147 there between. The wrap
spring 147 is frictionally engaging the holder ring 142 and can be
premounted therein for ease of assembly. The wrap spring 147 has
inwardly directed tangs 153 on its opposite ends of which one is
visible in FIG. 13. The driving hub 111 has an axially extending
key 161 that engages between two fingers 154, 156 on a chain wheel
135 that are complementary to the key 161. The inwardly directed
tangs 153 upon assembly are occupying the respective free spaces
between the axially extending key 161 and the complementary fingers
154, 156. The chain wheel 135 is received on the driving hub 111 in
a manner that allows a limited amount of relative rotation between
the chain wheel 135 and the driving hub 111. The amount of limited
rotation is determined by the relative positioning of the key 161
and fingers 154, 156 and the spring tangs 153 there between. The
driving hub 111 is rotatably journalled on the chain cover by means
of a ball bearing 137 encased between opposite complementary
runways 136, 138. A looped driving chain (deleted for clarity from
FIG. 13, but shown in FIGS. 14, 15) can engage the chain wheel 135
for inducing rotation to the driving hub 111. The looped driving
chain 115 (see also FIGS. 14 and 15) is guided to the exterior of
the chain cover 113 by a special chain guide that is composed of
two opposite identical chain guide halves 173. These chain guide
halves 173 are attached to the chain cover 113 by a front cover 175
and fasteners 177 that engage a back plate 179 through
corresponding openings in the front cover 175, chain guide halves
173 and chain cover 113. The remaining parts of the driving member
103 are assembled by a pin 139 engaging through a coil spring 181,
a central opening in the chain cover 113, with the stationary
connector 117A. The stationary connector 117A will then be in
non-rotatable engagement with an inner perimeter surface of
protrusion 117B on the chain cover 113. The special chain guide
will now be described in reference to FIGS. 14 and 15. The FIGS. 14
and 15 show the chain wheel 135 isolated from the rest of the
driving member 103, but with the driving chain 115 and the chain
guide halves 173. Each of the chain guide halves 173 as shown in
FIG. 14 is composed of a relatively hard wear resistant cover 173B
that cooperates with a relatively soft elastomeric base member
173A. The arrangement of a necessary wear resistant surface as a
thin cover element 173B over resiliently flexible, elastic base
element 173A, successfully reduces noise production of the operated
operating chain 115 over the wear resistant surface of the cover
173B. This makes for a low noise chain driving member 103.
[0044] Shown in FIG. 16A is the engagement between the shaft brake
module 5 and the driving member 103. This engagement, although it
is shown in combination with the second embodiment of driving
member 103, is also valid for the first embodiment of FIGS. 1 to
10B. In particular FIG. 16A illustrates that the shaft brake module
5 can engage the driving member 103 from a slightly angular
position, which is convenient when manoeuvring the winding shaft
(deleted from FIGS. 16A to 16B), between opposite mounting
brackets. To enable this slight angular position, the outer brake
sleeve 51 is provided with an undercut area 185 leading up to its
internal splines 67 and guiding these internal splines into
engagement with the driving hub 111. Similarly, the stationary
connector 117A has a widened area 187, helping the splined end
section 69 into engagement with the stationary connector 117A. In
FIG. 16B the relevant portion of FIG. 16A is shown on an enlarged
scale. The ability of coupling a preassembled winding shaft to a
driving member that has been preliminary installed is of particular
importance when the winding shaft is combined with a spring assist
module. In such assemblies it is particularly beneficial when the
pretension or preloading of the spring assist module can be preset
at the factory, without having to worry about the final engagement
between the winding shaft and the driving member. Only when there
is used a chain stopper within the operating chain loop, there
needs to be the additional instruction to first operate the driving
member without the winding shaft engaged, until it is in the fully
raised position. Without an end stopper the winding shaft can be
engaged in any position of the driving member. Only when removing
and reinstalling the winding shaft during use it will be important
to take account of the position of retraction or extension in which
the winding shaft is removed. Otherwise the original amount of
spring assist may not be properly re-established.
[0045] Additionally visible in FIG. 16A is that the chain cover 113
on its reverse side is provided with hooks 189, 191 for connecting
the driving member 103 to a mounting bracket (not shown, but
conventional). The connector pin 139 is resiliently urged to an
extended position by the coil spring 181, so that it may latch and
retain the chain cover 113 to the bracket (not shown, but
conventional) once the hooks 189, 191 have engaged this
bracket.
[0046] FIGS. 17 and 18 show in both exploded and assembled forms a
winding shaft drive 101A with again the optional addition of a
spring assist module 21. For further details about the spring
assist module 21 reference can be had to the description of FIGS. 2
and 3 and to applicant's published international patent application
WO 2010/089118. One particular advantage of the combination of a
shaft brake module 5 and a spring assist module 21 according to the
embodiment of FIGS. 2 and 3 and of FIGS. 17 and 18, is that the
spring assist module 21 can be pretensioned in the winding shaft
through the shaft brake module 5. The shaft brake module 5 will
then keep the spring assist module 21 in its pretensioned
condition, while it is disconnected from the driving member 103.
The pretensioning of the spring assist module 21 can conveniently
be performed at the assembly plant, so that is needs no adjustment
from the end user. The assisting force of the pretensioned spring
assist module 21 will thereby only act on the winding shaft during
rotation thereof by the driving member 3, 103. Once adjusted to a
new position of retraction or extension, the weight of the winding
covering that will be associated with the winding shaft drives 1A,
101A will be held by the shaft brake module 5.
[0047] In FIG. 19 another variation 102A of the second embodiment
is shown in cross section. The variation of winding shaft drive
102A is somewhat similar to that of FIG. 12, but benefits from the
addition of a spring assist module. To couple the connector sleeve
25 of the spring assist module 21 to the stationary connector 117
of the driving member 103, an additional connecting shaft 195 may
be provided. The connecting shaft 195 extends through the central
opening 108 of the standard adapter 106 as shown in FIG. 12. This
arrangement is useful when spring assistance is desired for a
particular window covering, that is to be operated by the winding
shaft drive 102A, but when the shaft brake integrated in the
driving member 103 is still sufficient for holding it in
position.
[0048] Accordingly is described a winding shaft drive 1, 1A, 101,
101A, 102, 102A that is arranged for operating a retractable
covering for an architectural opening. This winding shaft drive
includes an at least partially hollow winding shaft 7, a driving
member 3, 103 for inducing rotation to the winding shaft, and a
shaft brake adapted to be operated by the driving member. The shaft
brake as described includes a preassembled module 5 for
accommodation in the at least partially hollow winding shaft 7 and
has first coupling means 67 on one axial end thereof for
transmitting rotating forces and second coupling means 69 on the
same one axial end for transmitting non-rotating stationary forces.
The driving member as further described has a driving hub 11, 111
for disconnectably coupling to the first coupling means 67 and a
stationary connector 17, 17A, 117, 117A for disconnectably coupling
to the second coupling means 69. Further a shaft brake module 5 and
a driving member 3, 103 have been described that are specifically
adapted for use in this winding shaft drive.
[0049] It is thus believed that the operation and construction of
the present invention will be apparent from the foregoing
description. The invention is not limited to any embodiment herein
described and, within the purview of the skilled person;
modifications are possible which should be considered within the
scope of the appended claims. Equally all kinematic inversions are
considered inherently disclosed and to be within the scope of the
present invention. In the claims, any reference signs shall not be
construed as limiting the claim. The term `comprising` when used in
this description or the appended claims should not be construed in
an exclusive or exhaustive sense but rather in an inclusive sense.
Thus the expression `comprising` as used herein does not exclude
the presence of other elements or steps in addition to those listed
in a claim. Furthermore, the words `a` and `an` shall not be
construed as limited to `only one`, but instead are used to mean
`at least one`, and do not exclude a plurality. The mere fact that
certain measures are recited in mutually different claims does not
indicate that a combination of these measures cannot be used to
advantage. Expressions such as: "means for . . . " should be read
as: "component configured for . . . " or "member constructed to . .
. " and should be construed to include equivalents for the
structures disclosed. The use of expressions like: "critical",
"preferred", "especially preferred" etc. is not intended to limit
the invention. Features which are not specifically or explicitly
described or claimed may be additionally included in the structure
according to the present invention without deviating from its
scope.
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